Physical Origin Of EIT

The physical origin of the transparency window can be understood by realizing that the beat of the probe field and the coupling laser induces a time-varying radiation-pressure force. If the beat frequency matches the mechanical oscillation frequency, then the mechanical oscillator is driven resonantly. The driven oscillator in turn creates sidebands on the intra- cavity field. Considering the strong-coupling laser only, in the resolved-sideband limit, the lower motional sideband is far off cavity resonance and can be neglected. In contrast, the upper sideband of the coupling laser, created by the mechanical motion, has precisely the same frequency as the probe field and is moreover phase coherent with the probe field. This leads to an interference that yields a cancellation of the intracavity field on resonance, giving rise to the transparency window. The phenomenon thereby results from the destructive interference between reflection amplitudes for photons scat- tered from the coupling laser and photons of the probe field. The effect of higher-order sidebands was discussed by Xiong et al. (2012).

REVIEWS OF MODERN PHYSICS, VOLUME 86, OCTOBER–DECEMBER 2014

Cavity optomechanics